University of Illinois environment and behavior researcher Dr. Frances "Ming" Kuo did meticulous and thorough studies of the effects of nature contact on human mental and physical health. The definitive conclusion? Green environments are "an essential component for good health."

And nature contact is just as important for our physical health as our mental health. The studies also show:

• By contrast, environments with less green space are associated with greater rates of childhood obesity; higher rates of 15 out of 24 categories of physician-diagnosed diseases, including cardiovascular diseases; and higher rates of mortality in younger and older adults.

In case you were wondering if this result was just because rich people live in greener neighborhoods with more parks, Dr. Kuo reports that "While it is true that richer people tend to have both greater access to nature and better physical health outcomes, the comparisons here show that even among people of the same socioeconomic status, those who have greater access to nature, have better physical health outcomes. Rarely do the scientific findings on any question align so clearly."

So the message is clear. "Because of this strong correlation between nature and health, Kuo encourages city planners to design communities with more public green spaces in mind, not as mere amenities to beautify a neighborhood, but as a vital component that will promote healthier, kinder, smarter, more effective, more resilient people."

Previous research over the last few decades had indicated that green environments are critical to various aspects of human health, but the University of Illinois studies, undertaken with exceptional scientific rigor, now confirm what many of us have known for years: green environments aren't a luxury but a necessity for all people. And since we know that for millenia our species lived and evolved in green, natural environments, why should be be surprised? Every animal on our planet thrives in the environment in which it evolved and can become ill or go crazy in alien environments like zoos or cages (or sterile factories or blighted urban and rural environments).

Let's hope that more communities pay attention to what the science is telling us! Every time we cut down trees, underfund a park or raze a natural area to build a mall or more suburbs, we're destroying an essential component of human mental and physical health.